Saturday, September 24, 2005

If a mountain fell in the Alaska wilderness . . .

Jackie Caplan-Auerbach was checking earthquake activity at Alaska volcanoes from her Anchorage office on September 14th, a routine she performs every day at the Alaska Volcano Observatory, when she noticed a strange seismic signal on Mount Spurr.

A view of an enormous rock delta from the avalanche of Mt. Steller that registered on seismometers all over Alaska. The amount of rock and ice that fell was equal to a pile one mile long, one-third mile wide, and 50 yards high.

Ruedi Homberger photo, courtesy of Ultima Thule Lodge.

A large shock to the earth-not as abrupt as an earthquake-had happened somewhere in Alaska. When Caplan-Auerbach saw the odd signal was even stronger on Mount Wrangell, she suspected there was a great avalanche somewhere in the restless corner of Alaska where the panhandle of Southeast meets the rest of the state.

There was. A good chunk of Mount Steller, a razorback 10,000-foot peak about 80 miles east of Cordova, had collapsed onto Bering Glacier. Rocks and ice from the mountain tumbled 8,000 vertical feet, spilling out in a chunky black delta that reached six miles from the mountain. Christian Huggel, a Swiss avalanche specialist who happened to be visiting the Alaska Volcano Observatory in Anchorage, estimated that the amount of rock and ice that shook loose was equal to a pile one mile long, one-third mile wide, and 50 yards high.

Caplan-Auerbach studies avalanches on Iliamna Volcano, but the largest recorded avalanches there are about one-fifth of the size of the recent event at Mt. Steller.

"We've seen big ones, but we've never seen them generate seismic signals like this," she said. "It's a monster."

Scientists at the Alaska Tsunami Warning Center in Palmer also noticed the avalanche when it happened. They called the Alaska Earthquake Information Center at the University of Alaska Fairbanks to confirm.

"It showed on all our instruments on mainland Alaska," Natalia Ruppert of the earthquake information center said, adding that the amplitude of the event was about equal to a magnitude 3.8 earthquake, and more than 200 seismometers all over the state picked up its vibrations.

Scientists who monitor infrasound waves-signals with frequencies too low for humans to hear, generated by blasts from underground nuclear bombs and winter storms in the Gulf of Alaska, among other sources-also detected the avalanche from Fairbanks, 330 miles away from Mount Steller.

Sometimes large earthquakes trigger massive avalanches, as happened in 2002 when the Denali Fault earthquake shook acres of rocks over Black Rapids and other glaciers, but Mount Steller broke for reasons unknown.

"It's one of those big puzzles," Caplan-Auerbach said. "A lot of these (steep mountains) probably sit right on the verge of failure."

In her studies of Iliamna Volcano, Caplan-Auerbach has found that avalanches like the one on Mount Steller sometimes rumble one-half hour to two hours before they collapse, possibly due to the fracturing of ice at the base of the avalanche material. She just submitted a paper on the curious tendency of some avalanches to move before they collapse.

One of the unique features about the giant avalanche of September 14, 2005 on Mount Steller was that perhaps no one saw it or felt it. The nearest settlements, tens of miles away, were too far for people there to feel the rumbling.

"It shows how wonderful Alaska is," Caplan-Auerbach said. "Places like Iliamna could break in half and nobody would be killed."

Friday, September 23, 2005

Major Storm batters Western Alaska coast

A major storm sweeping through the Bering Sea is causing widespread flooding in coastal villages throughout western Alaska. Some of the hardest-hit areas are communities in Norton Sound, including Nome. But the affected areas stretch for hundreds of miles.

High winds from the south, coupled with a large storm surged, brought the crashing surf into Nome, spreading water onto Front Street.

U.S. Senate bill has millions for Alaska

Finally, some small relief for Rural Alaska Villages:

"The U.S. Senate approved an agriculture spending bill Thursday maintaining several multimillion dollar programs in Alaska that Sen. Ted Stevens developed during his chairmanship of the Senate Appropriations Committee.

The Senate bill would put $26 million into grants and loans for rural water and sewer systems during the coming federal fiscal year. That's the same amount as was provided in the current year's spending bill.

Another $28 million would go to energy projects in areas with extremely high energy costs, mostly in Alaska. Again, the figure is the same as this year's.

The third program, to build community facilities, would route $20 million to areas of extreme unemployment, again mostly in Alaska. The total would be down $1 million from the current year.

The Senate bill must still be merged with a House version and signed by the president, but Stevens has in past years succeeded in protecting such earmarks during that process.

Other Alaska earmarks in the Senate's spending plan for the Agriculture Department include:

* $3.47 million for education grants to institutions that serve Alaska and Hawaii Natives.

* $1 million for berry research at the University of Alaska Fairbanks.

* No change in funding to UAF for virus-free potato research, and nuisance insect management and seafood waste studies.

Coming To The Arctic Near You: The Longer, Hotter Summer

FAIRBANKS,AK--In a paper that shows dramatic summer warming in arctic Alaska,scientists synthesized a decade of field data from Alaska showingsummer warming is occurring primarily on land, where a longer snow-freeseason has contributed more strongly to atmospheric heating than havechanges in vegetation.

Arctic climate change is usually viewed as caused by theretreat of sea ice, which reduces high-latitude albedo- a measure ofthe amount of sunlight reflected off a surface - a change mostpronounced in winter.

"Summer warming is more pronounced over land than over sea ice,and atmosphere and sea-ice observations can’t explain this," said TerryChapin, professor of ecology at the University of Alaska Fairbanks’Institute of Arctic Biology and lead author of the paper which appearsin the September 22, 2005 advance online publication Science Express,

Using surface temperature records, satellite-based estimates ofcloud cover and energy exchange, ground-based measurements of albedoand field observations of changes in snow cover and vegetation, Chapinand co-authors argue that recent changes in the length of the snow-freeseason have triggered a set of interlinked feedbacks that will amplifyfuture rates of summer warming.

"It’s the changes in season length rather than increases invegetation that explains this observation," Chapin said. Summer warmingcorrelates with a lengthening of the snow-free season that hasincreased atmospheric heating locally by an amount similar in magnitudeto the regional heating expected over multiple decades from a doublingof atmospheric carbon dioxide, say the authors.

"Snowmelt is 2.5 days earlier for each decade we studied, Chapin said.Twomechanisms explain the pronounced warming over land during the summer.First, the early snow melt increases the length of time the landsurface can absorb heat energy. Second, the increase in snow-freeground permits increases in vegetation such shrubs and advances oftreelines.

"Continuation of current trends in shrub and tree expansioncould further amplify this atmospheric heating 2-7 times," Chapin said.

"This mechanism should be incorporated into climate models,"Chapin said. Improved understanding of the controls over rates of shrubexpansion would reduce the likelihood of surprises in the magnitude ofhigh-latitude amplification of summer warming.

Researchers were funded by the National Science Foundation,Office of Polar Programs, ARCtic System Science program--the goal ARCSSis to answer the question: What do changes in the arctic system implyfor the future?